1. Field of Invention
Embodiments of the present invention generally relate to semiconductor packages, electronic system such as integrated circuit (IC) cards incorporating semiconductor packages, and methods of manufacturing the same. More particularly, embodiments of the present invention relate to semiconductor packages that increase contact area between a surface of the semiconductor package and an opposing surface of a card body and methods of manufacturing the same. Other embodiments of the present invention relate to semiconductor packages having reduced thicknesses and methods of manufacturing the same.
2. Description of the Related Art
A chip-on-board (COB) type semiconductor package is typically used to manufacture IC cards, e.g., smart cards. The IC cards are commonly used nowadays in various applications, replacing magnetic cards.
Referring to FIG. 1, the COB type semiconductor package includes a semiconductor chip 3 attached to a top surface of a semiconductor package substrate 4. An active surface 3a of the semiconductor chip 3 is electrically connected to a metal layer 5 disposed on another surface of the semiconductor package substrate 4 opposite the top surface, using bonding wires 6 that extend through wire holes 4a defined in the semiconductor package substrate 4. The bonding wires 6 are generally needed as the active surface 3a is disposed over the top surface of the semiconductor package substrate 4, opposite to the surface on which the metal layer 5 is disposed. The COB type semiconductor package is coupled to a card body 2 using an adhesive (not shown) between a surface 1a of the COB type semiconductor package and an opposing surface of the card body 2. In particular, the COB type semiconductor package is disposed within a cavity 2a defined in the card body 2.
The bonding wires 6 inevitably protrude from the active surface 3a of the semiconductor chip 3 to a certain height, thereby forming a loop where the wires 6 extend away from the active surface 3a and then bend toward the metal layer 5. An encapsulant 9 is also provided so as to encapsulate the wires 6. A sufficient amount of encapsulant 9 must be, therefore, provided to protect the wires 6 from the external environment. Accordingly, the encapsulant 9 creates a relatively large molding region “B”, leaving a relatively small bonding region “A” where the surface 1a of the semiconductor package and an opposing surface of the card body 2 can be bonded to each other. Furthermore, because the bonding wires 6 need to be formed on both sides of the semiconductor chip 3, the length of the molding region “B” is additionally increased and the length of the bonding region A is further reduced while the total length of the available package system is limited.
It has been also discovered that edges of the substrate 4 tend to deform during manufacturing of the COB type semiconductor package. Thus, because the bonding region “A” is relatively small with the conventional system, the substrate 4 tends to separate from the card body 2 and the resulting IC card can be easily damaged or broken.
These problems can become more severe as the size of the semiconductor chip 3 increases and the package system or the IC card is subject to a harsher environment.
FIG. 2 is a cross-sectional view of another conventional package system to solve the above discussed problems.
Referring to FIG. 2, a conventional package system can be provided as a flip-chip-type COB package system. As shown in FIG. 2, an IC card includes a card body 12 having a cavity 12a defined therein. A semiconductor chip 13 attached to a semiconductor package substrate 14 to form a flip-chip-type COB semiconductor package. In the flip-chip-type COB semiconductor package, the active surface 13a of the semiconductor chip 13 is electrically connected to a metal layer 15, using conductive bumps 18 which are coupled to intermediate metal layers 17. In turn, the intermediate metal layers 17 are electrically connected to metal layers 15 by conductive vias 16 that extend through the package substrate 14. The semiconductor package is bonded to the card body 2 using an adhesive (not shown) between a surface 11a of the flip-chip-type COB semiconductor package and an opposing surface of the card body 2.
The conductive bumps 18 protrude from the surface of the semiconductor chip 13 away from a bottom surface of the cavity 12a and an encapsulant 19 is provided so as to encapsulate the conductive bumps 18. However, a sufficient amount of the encapsulant 19 must also be provided to adequately fix the semiconductor chip 13 to the intermediate metal layers 17 and the substrate 14.
Accordingly, the encapsulant 19 maintains a relatively large molding region “B”, leaving a relatively small bonding region “A” where an adhesive can be applied between the surface 11a of the semiconductor package and an opposing surface of the card body 12. The substrate 14 or the semiconductor package also tends to separate from the card body 12 as in the IC card discussed in FIG. 1. Moreover, the presence of the intermediate metal layers 17 tends to increase the overall thickness “T” of the flip chip type COB semiconductor package system and increase the cost and complexity of manufacturing the flip-chip-type COB package system. Thus, even with the package system discussed with respect to FIG. 2, the above discussed problems are not sufficiently solved.
The present invention addresses these and other disadvantages of the conventional art.